1. Field of the Invention
The present invention relates to a successive screw driving attachment for successively driving screws in order to fasten sheets or boards made of wood, metal, gypsum, or the like to floors or walls, and more particularly to a successive screw driving attachment with which screws can be smoothly fed to the driving position of a bit.
2. Prior Art
There have been proposals in the past for a successive screw driving attachment that is attached to an electric screwdriver and that successively drives screws in order to fasten sheeting made of wood, metal, gypsum, or the like to floors or walls. As shown in FIG. 12, this type of successive screw driving attachment 101 has a screw feed mechanism 103 attached slidably in the driving direction of a screw S to a driver unit casing 102 that is used by being detachably connected to an electric screwdriver D.
This successive screw driving attachment 101 turns the S (corresponds to a standard screwdriver tool) with a rod-shaped bit 104 that drives the screw S, drives this screw S into a sheet or board, and at the same time gradually retracts the screw feed mechanism 103 within the driver unit casing 102. The driving of the screw S is then concluded at the point when the distal end of this bit 104 is at roughly the same position as the distal end portion 103a of the screw feed mechanism 103.
This successive screw driving attachment 101 makes use of a screw rope SR in which numerous screws S are stung onto a plastic rope. This screw rope SR is incrementally played out to the driving position of the bit 104 in interlock with the driving operation in the screw feed mechanism 103. When this successive screw driving attachment 101 is used, the trigger switch on the grip handle of the electric screwdriver D is pulled, the bit 104 is turned by the motor of the electric screwdriver D, the distal end of the bit 104 is engaged with the head of the screw S at the distal end of the screw rope SR loaded in the screw feed mechanism 103, and [the screw S] is driven into the sheeting or other material by the rotation of this bit 104.
Problems which the Invention is Intended to Solve
Because a feed lever 105 for the screws S see-saws back and forth in the conventional screw feed mechanism 103 described above, the operation in which the screws S of the screw rope SR are grabbed by a screw feed prong 106 and fed to the driving position does not itself pose any problems. When the driving of a single screw S is complete, however, the next screw S is fed to the driving position while the screw feed mechanism 103 is still being pushed back to the distal end, so there is a problem in that the head of this next screw S hits the distal end of the bit 104.
With the conventional successive screw driving attachment 101, when the screw rope SR was loaded into the screw feed mechanism 103, the first screw S had to be fed to the driving position by pressing this screw feed mechanism 103 against the sheeting once to effect the reciprocal action of the screw feed prong 106. Also, a multi-step operation had to be carried out when the work of driving the screws S was complete and the screw rope SR was to be taken out of the screw feed mechanism 103 while still partially unused.
Furthermore, the attachment position of the rope R varied with the type of screws S being used. Because the position of the rope guide path of the screw feed mechanism 103 varied according to the length of the screws S, screws S with different attachment positions for the rope R could not be loaded into the same screw feed mechanism 103. Moreover, since a single successive screw driving attachment 101 could only accommodate a narrow range of screw lengths, a dedicated successive screw driving attachment 101 had to be used for short screws, and another dedicated successive screw driving attachment 101 for long screws, meaning that a plurality of successive screw driving attachments 101 were required.
Another problem was that when the conventional successive screw driving attachment 101 was used on a floor, the worker had to operate the successive screw driving attachment 101 while bending over or kneeling, so the worker tended to become fatigued when working for an extended period. In view of this, there has been a need for the proposal of a successive screw driving attachment with which driving work could be performed while the worker was standing.
The present invention was conceived in light of the above problems, and it is an object thereof to provide a successive screw driving attachment with which the screw rope can be smoothly loaded to the driving position by delaying the timing at which the screws are fed to the driving position with a stopper provided to the feed lever of the screw rope, and with which there is no need to fed the first screw of the screw rope up to the driving position, and the screw rope can be removed with one finger.
In order to achieve the stated object, the successive screw driving attachment pertaining to the present invention is a successive screw driving attachment in which a screw feed mechanism and a distal end screw guide are provided to the front part of a driver unit, and a coupling tube for connecting to an electric screwdriver via a coupling adapter is provided to the rear part of the driver unit, the essence of which is that the driver unit forms a guide tube into which a bit is inserted, an elastic member is mounted for pressing the screw feed mechanism forward so that it is slidable in the longitudinal direction of the guide tube, and there is a drive depth adjustment mechanism that adjusts the depth to which the screw is driven by the bit, the screw feed mechanism is provided with a screw feeder comprising a screw feed prong that sequentially feeds the screws on a screw rope, in which numerous screws are lined up and attached to a rope, to the driving position of the bit in interlock with the longitudinal sliding of the driver unit that accompanies the driving action produced by the bit in the distal end screw guide, the screw feeder is structured such that the screw feed prong instantly feeds the next screw to the driving position when the screw feed mechanism has been pushed back to the distal end, and the distal end screw guide has a rope guide path for the screw rope, and has formed in it a screw feed hole for the reciprocal action of the screw feed prong.
With the above constitution, the successive screw driving attachment can be easily coupled to an electric screwdriver via a coupling adapter. In particular, a single successive screw driving attachment can be coupled to a number of different electric screwdrivers by exchanging the coupling adapter.
In the use of the successive screw driving attachment pertaining to the present invention, the first step is to load the screw rope into the distal end screw guide, which places the screw at the front of the screw rope in the driving position. The motor of the electric screwdriver is rotated, the contact face of the distal end screw guide of the screw feed mechanism is pressed against the sheeting or other material, and the bit is turned so that the screw can be gradually driven into the sheeting or other material. Simultaneously with this driving of the screw, the screw feed mechanism (the distal end screw guide) gradually retracts within the driver unit, the distal end screw guide that is integrated with this screw feed mechanism collides with and stops at a drive depth adjustment mechanism housed in the driver unit, and this disengages a clutch and concludes the driving of the screw.
When the distal end screw guide is removed from the sheeting, the screw feed mechanism is pushed back to its original position at the distal end, the screw feed prong of the screw feeder operates and instantly feeds the next screw on the screw rope to the driving position of the distal end screw guide, and screw driving work can then be performed in the same manner as above. Screws can be driven successively by repeating this operation over and over.
The screw feed mechanism has a feed lever that is formed in an approximate caret shape and is attached rotatably around a fulcrum, the driven portion of this feed lever is engaged with a cam housing formed in the driver unit, and the screw feed prong on the free portion of the feed lever is reciprocally operated. Also, a stopper for keeping the screw rope in a feed standby state is provided to the feed lever, and the stopper is released when the screw feed mechanism has been pushed back to the distal end in the screw driving operation, allowing the screw feed lever to be operated instantaneously
This action of the stopper of the feed lever allows the screw feed prong to be kept in the standby state it is in before a screw is fed to the driving position while the screw feed mechanism is being pushed back in the distal end direction upon completion of the driving of one screw and while a screw is being driven by the bit. After this, the next screw will not be fed to the driving position before the screw feed mechanism has been completely pushed back to the distal end, which prevents the head of the screw from hitting the distal end of the bit. Once the screw feed mechanism has been completely pushed back to the distal end, the stopper of the feed lever is released, and the next screw can be instantaneously fed to the driving position.
The screw feed prong is a member formed in the shape of a rod, and is rotatably attached to the free portion of the feed lever so as to be roughly parallel to the feed direction of the screw rope and so that the distal end side thereof projects to the driving position.
Because this screw feed prong has a narrow swing angle, it just needs to be tilted a little for the loading of the screw rope to be completed quickly. Also, the screw rope can be easily removed from the distal end screw guide by pressing the screw feed prong from the outside upon completion of the driving of a screw.
The screw feed mechanism can be structured such that the distal end screw guide can be detachably attached. For instance, screws can be driven into a sheeting material in a constantly stable state by installing a distal end screw guide equipped with a long screw guide tube on the screw feed mechanism when long screws are used, and a distal end screw guide equipped with a short screw guide tube when short screws are used.
A bracket can be attached to the coupling adapter, and an arm having a grip can be detachably attached to this bracket. If an arm having a grip is thus attached to the rear of the coupling adapter, the driving work can be performed by holding the grip of the arm, rather than the grip handle of the electric screwdriver. This makes it possible for the worker to drive screws into a floor while standing upright. Also, screws can be driven into ceilings and other high places without the worker having to stand on a ladder.